Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-10-35
May 24, 2010
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin is being issued to
remind owners, operators, and installers of potential hazards and
airworthiness concerns related to having loose equipment in the flight
compartment; particularly items placed on the glare shield. It was
prompted by a recent event on a Mitsubishi MU-2B, applies to all
aircraft that have a glare shield installed above the instrument panel,
and is of particular concern to aircraft with windshield heating
systems where the power terminal strips may be exposed and subject to
an electrical short from a foreign object placed on the glare shield.
The airworthiness concern does not address an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) Part 39.
Background
During recent flight on a Mitsubishi MU-2B, thick black smoke filled
the cockpit and the crew was forced to make an emergency landing. It
was discovered that a hand-held GPS receiver and antenna had been set
on the glare shield. A metallic portion of the GPS antenna
inadvertently made contact across the windshield heater terminal
strips, resulting in an electrical short circuit. The resulting current
flow caused the loose equipment to burn, resulting in smoke in the
cockpit.
Recommendations
The FAA reminds owners and operators of aircraft that loose equipment
on the glare shield or in the cockpit can present a hazard,
particularly for aircraft with a windshield heater system installed
where electrical terminal strips may be exposed and subject to short
circuit. Owners and operators should recognize the potential for
exposed terminal strips to be attached to high current windshield
heating systems and refrain from placing any loose items on the glare
shield that might cause an electrical short and subsequent electrical
fire. If possible, these terminal strips should also be insulated or
covered to mitigate such an occurrence.
The FAA also reminds owners and operators that loose or portable
equipment on the glare shield can obscure the field of view of the
crew, can potentially influence the magnetic compass accuracy, and can
become a hazard in turbulence. Owners and operators should secure loose
or portable items and equipment properly prior to and during the
flight, should isolate portable or loose equipment from other equipment
installed, and should ensure the magnetic compass is not affected by
any magnetic or electrical influence from portable or loose equipment.
For Further Information Contact
Les Lyne, Aerospace Engineer, Small Airplane Directorate, 901 Locust,
Kansas City, MO 64106; phone: (816) 329-4171; fax: (816) 329-4090;
e-mail: leslie.lyne@faa.gov.